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Pulmonary Function Test Quality in the Elderly – A Comparison with Younger Adults Respir Care 2014;59(1):16-21. Gregg Ruppel, MEd, RRT, RPFT, FAARC Adjunct.

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Presentation on theme: "Pulmonary Function Test Quality in the Elderly – A Comparison with Younger Adults Respir Care 2014;59(1):16-21. Gregg Ruppel, MEd, RRT, RPFT, FAARC Adjunct."— Presentation transcript:

1 Pulmonary Function Test Quality in the Elderly – A Comparison with Younger Adults Respir Care 2014;59(1): Gregg Ruppel, MEd, RRT, RPFT, FAARC Adjunct Professor Pulmonary, Critical Care and Sleep Medicine Saint Louis University School of Medicine

2 Research Question Can elderly patients achieve quality scores for spirometry and DLco comparable to a younger adult population? Why this is important : 1.Spirometry and DLco both involve elements of patient effort and cooperation to provide valid data 2.Spirometry and DLco each have significant evidence-based indications related to evaluation of lung function 3.The population is ageing

3 Background Literature Refs Mini Mental State Examination (MMSE) commonly used to grade cognitive impairment – <17 severe impairment, mild, normal – Patients WITH cognitive dysfunction have difficulty performing spirometry

4 Background Literature Refs Most elderly subjects without cognitive dysfunction can perform acceptable spirometry – Acceptability and reproducibility of spirometry ranges from ~70 – 95% – FEV 1 tends to be more repeatable in the elderly – Age itself does not appear to be a limiting factor – Misdiagnosis of COPD & asthma common

5 Background Literature Refs DL CO acceptability/repeatability in the elderly not well documented – Younger age may be predictive of poor quality (unable to inspire maximal IVC) Most studies of spirometry and DLCO quality used older standardization recommendations

6 Methods Retrospective review (22 months) – All patients (elderly & younger) included – Elderly:> 80 years – Controls:ages years Sample size dependent on time frame – Post hoc power analysis Sources of bias: hospital based PFT lab

7 Methods Data quality – ATS/ERS 2005 recommendations to assess quality – Software QA grading system used – Over-read by chief technologist – Lab QA included monthly/quarterly tech feedback – Equipment QC and biologic controls within limits Predicted values – GLI (ages 3-95) used for % predicted and LLN

8 Percent Predicted vs LLN Quanjer et al, Eur Resp J Epub 2012 LLN = 5 th centile; using 80% introduces age-related bias

9 Methods Statistical Analysis – Categorical data: Fisher’s exact test – Continuous variables: Student t-test unpaired means Mann-Whitney U test unpaired medians – Data reported as mean±SD or median w/interquartile ranges – Two-tailed p <0.05 significant – Post hoc power analysis

10 Spirometry QA (fig. 1)

11 DLCO QA (fig. 1)

12 Results Demographics

13 Results Spirometry Elderly (n=150) Control(n=178) p

14 Results DL CO Elderly (n=150) Control(n=178) p

15 Results Spirometry & DL CO Quality

16 Most common reason for spirometry test failure (elderly and controls): exhalation 5% Most common reason for DLCO test failure: not stated (inability to inspire 85% of VC) Post hoc power analysis – generally not useful but may explain why no significant differences were observed Results

17 Discussion Under-diagnosis, over-diagnosis, and misclassification are all problems related to elderly Asthma and COPD are common problems, amenable to treatment if properly diagnosed Elderly patients WITHOUT cognitive impairment can perform spirometry and DLCO acceptably and reproducibly

18 Discussion What this study adds Acceptability/repeatability for spirometry and DLCO are similar for elderly (notably >80 years) and younger subjects High levels of data quality are achievable using procedures that strictly adhere to current ATS/ERS guidelines AND utilizing a laboratory QA program Data with B or C quality scores are useable

19 Discussion Potential study limitations Bias associated with: – Lack of diversity (race) – Hospital lab referrals (lung dysfunction?) – Cognitive impairment not evaluated – Equipment (software grading of test quality) – Technologist skill/experience/motivation

20 Take Home Message(s) Elderly subjects can perform acceptable and repeatable spirometry and DLCO similar to younger subjects A comprehensive lab QA program likely contributes to high rates of acceptable tests Predicted sets need to be carefully selected, particularly when elderly subjects are being evaluated

21 Editorial Comments An editorial from Sorensen accompanies the Haynes paper and makes 2 important points – Misdiagnosis and/or misclassification of asthma and COPD in older subjects can be reduced by good quality PFTs – Readmission of patients with COPD has real world consequences ($$) and better diagnostics (PFTs) should help to improve disease management

22 Thanks! Gregg Ruppel, Med, RRT, RPFT, FAARC


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